In DE-GM No. 85 05 266 there is disclosed a simple and inexpensively constructed, purely mechanically operated apparatus, which measures energy expended at an operating member that nevertheless achieves very dependable measurements. In that apparatus, the friction drive is provided by a friction wheel and friction member. Unfortunately, in such an arrangement, conditions of easily appearing slippage between the rubbing pieces, due to contamination or frictional wear, can falsify somewhat the measurement values.
A similar apparatus is known from DE-GM No. 82 03 421 by which the energy transfer to the counting mechanism results by means of a rack drive operating in combination with a ratchet for the prevention of a reverse rotation. However, this known solution has drawbacks in that it is comparatively expensive to construct and, further in that flexing movements of the operating member, which would only cause an additional rotation of the control gear smaller than the angular separation of two ratchet teeth of the ratchet gear in the ratchet, are lost. The measurements made thereby are, for this reason, not quite precise.
Thus, it can be seen that there remains a need for an apparatus of the type described, so that a more precise measurement of the energy expended at the operating member is made possible, whereby nevertheless the simple and inexpensive mechanical construction of the apparatus are maintained.
Accordingly, it is a primary goal of the present invention to provide a mechanical transmission system which realizes the concepts of the invention so there is achievable a precise as desired transmittance of the flexing movement.
In accordance with the teachings of the present invention a comb-shaped control spring is provided having tongues of differing lengths. As the control spring can be subdivided into tongues as thin as desired, as small as desired flexing movements can be transmitted herewith.
In further accordance with the teachings of the present invention, a reverse rotation of the control gear can be prevented by means of a second comb-shaped control spring that can be divided into tongues which are as this as desired.
In yet further accordance with the teachings of the present invention, the comb-like springs may be finely terminated at the ends of the tongues, whereby the fineness of this adjustment can be chosen as desired.
In still yet further accordance with the teachings of the present invention, the control gear includes a freewheel which transmits the finest flexing movements of the actuating member, yet immediately interrupts the transmittance during a reverse rotation. The actuating sensitivity of this freewheel can also be adjusted as desired by easy steps of the tradesman.
And in yet further accordance with the teachings of the present invention, the transmittance of the energy from the control member to the outer housing of this freewheel is provided either, by means of a friction transmission, or by means of an integral coupling of the control member and control gear, whereby the latter coupling is insignificantly more costly yet more dependable.